Coupling for armored cables



Dec. 6, 1 1,519,108

L. A. BROOKE COUPLING FOR ARMORED CABLES Filed July 5. 1923 'PatentedDec. 16, 1924. 1

UNITED. STATES morn A. BROOKE, on mmiovnn, MAR LAND cournme FOR ABMOREDcums.

I Appiiciztion filed J'u ly 5,

To all whom it may concem: 1 Be it known that I, LLOYD A. BRooKE,

' a citizen of the United States, residingatv useful Improvements inCouplin s for Ar- Landover, county of Prince George's, State ofMaryland, have invented certaln new and mored Cables; and I do herebyeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

The invention has for its object to provide a simple and effectivecoupling for joining the ends of armored cables, the coupling mitselfcomprising longitudmally 1nterlocking and mating armor sections,preferably in the form of half tubes, having interlockin hook flangesalong their meeting edges an their. portions provided with intween thesections, said insulatin terior helical threads toengage the corre-'spondingconvolutions of the cable armor, and complementary insulatingblocks fitting within the matin armor sections, said blocks being provied with mating ooves to form wire-receiving conduits an interlockingtongue and groove connections be;

blocks also preferably having .chambere or recessed end portions toreceive the ends of the cable armor and insulation, and opening into-thewire-receiving grooves.-

Typical applications of the invention are illustrated in theaccompanying drawing, in

which:

Fig. 1 is a side elevation of a T.-coupl1ng; Fig. 2 is an end viewpartly in section of the same, the section being taken on line 2-2 ofFig. 1; i Fig. 3 is a plan view of an insulating block section;

Fig. 4 is a side elevation thereof; Fig. 5 is an end elevation; Figs. 6,7 and 8 are views correspond ng to those in Figs. 3, 4 and 5 of themating block section;

Fig. 9 is a bottom plan view of a female insulating section, employed inconnection with a T-coupling or with a straight coupling;

Fig. 10 is a longitudinal section of a a straight coupling connectingtwo wire arof the inored cables;

Fig. 11 is a transverse sect onal elevation insulating blocks for atwo-wire cou- 1923;. "Serial 30. 649,572.

gitudinal edges of wlfich are provided with interlocking hook flangeswhich are adapt? ed to be snapped or the sections are assembled. In theembodiment of the invention as illustrated in Figs. 1 and 2, thecoupling is of the T-type, ad apted to connect a lateral branch to atwo-Wire armored cable in' which the armor of the cable is in the formof helical convolutions of metal, as shown. section 1 is provided with alongitudinal hook-like flange 4 along each longitudinal edge of the halftube members of the leg and head of the T, and correspondingly, thelongitudinaledges of the member 2 are provided with hook flanges 3,which are adapted to be either snapped over or. forced over orcedtogether when The T-shaped armor the'shoulders of the flanges 4 to forma secure interlocking joint or series of joints between the armorsections. Preferably, the

interlocking .faces of the hook flanges 3 and ously inter ocked with thearmor of the cale, as moreparticularly illustrated in Fig.

10, in which the grooves formed in-the ends of the coupling sections areindicated at 5. It will be understood, of course, that, if the conolutions of the armor on the cable. are of a difi'erent form than thatindicated, the grooves in the ends of the coupling section will be giventhe proper complementary form or contour to the cable armor.

Each complete coupling is provided with sectional insulating blocksadapted to subproperly register with stantially fill the interior of thecoupling and to provide recesses and channels'to receive the ends of thecable armor, the ends Y of the intermediate cable insulation, and theconducting wires, and retain these elements I of S111 ler diameterto'receive the slightly extended end of the cable insulation, saidrecess 12 opening into two longitudinal channels 13 and 14, which extendalong both faces of the angular member 10. Between the .grooves 13 and14 on the horizontal leg of the member -10 is formed a projecting tongue15,.and between the grooves on the vertical leg of the member 10 isformed a groove 16. The mating L-sha'ped insulating member shown inFigs. 6, 7 and 8 is in all essentials similar to that shown in Figs. 3,

5. 4 and 5, the only difference being the pro- 2 vision ofa tongue 16"on the vertical leg of the member 10, which tongue "engages the groove16 in the matingmember. To complete the sectional insulationassembly forthe T-cou ling, there is provided a third member. i ustrated in Fig. 9,which consists of a substantially semi-cylindrical block 20 providedwith end recesses 21, 21 and 22, 22, corresponding to the recesses 11and 12 in the L-shaped sections 10, which are. connected by two groovesor channels 23 and 24, which mate w1th the grooves Band 14 in themembers 10 and constitute conduits for the wires of the cable. Betweenthe rooves 23 and 24 there is formed an ad itional groove 25, whichengages the tongues'15 on the members 10.

To efl'ect a'T-eoupling, the cable armor is removed for a distancesomewhat less than the length of the head of the coupling armor and theinsulation below the cable armor is removed for a somewhat less distanceto leave'short lengths of the insulation 14 in said members 10.

projecting beyond the armor, and the final insulation for the wires isremoved adjacent the point where the wires are to be joined.

The armor on the cable section to be, cou

pled with that just referred to is similarly removed, so as to allow theend of the armor to project slightly within and fill the chamber formedby the mating recesses 11 in the lower ends of the insulating blocks 10.and

similarly, the intermediate insulation is severed so as to permit thesame to rojert beyond the armor to an extent to 11 the chamber formed bythe mating recesses .12 with the individual wires occupying the conduitsformed by the matin grooves 13 and e ends of the wires of this cablesection are then twisted about the wires of the other cable and preferably soldered together. The proper points for severing the armor andthe intermediate insulation on the respective cable sections may beaccurately determined-by placing the respective cable sectionsinoneflialt of the casing or armor section of the coupling, being surethat the convolutions on the cable armor engage the helical grooves inthe respective ends of the coupling section. After the wires of therespective cables are appropriately joined and secured by soldering, theconnected cables are removed from the half section of the coupling armorand the insulating blocks are then assembled about the joined cableswith the joined wires occupying the conduits formed by the matinggrooves in the insulating'blocks, the cable armor ends projecting intothe chambers formed in the ends of the insulating blocks, and theintermediate cable insulation sections occupying the intermediaterecesses in the insulation blocks. The armor sections of the couplingare then placed in position on either side of the assembled insulatingblocks, with the helical grooves in the open ends of the armor sectionsof the coupling in registry with the convolutions of the cable armor,and the two halves of the coupling armor are interlocked by forcing theflanges 3 and 4 thereon into engagement with each other, either bypressure, or if necessary, by hammer blows. If the armor sections of thecoupling are formed of metal or like material, as by drop forging, theywill possess sufiicient inherent resiliency to permit the parts to besnapped together by pressure on opposite sides and when so interlockedwill resist any ordinary stresses which would tend to separate them.When thus assem' bled and completed, the casing or armor sections of thecoupling are substantially rigid- 1 connected to the armor of the cablesections'and relieve the wires of all strain at the 'oint, so that theden er of disrupting the atter is practically tfiiminated. Furthermore,any movement of the wires with in the coupling is revented, and theindividual wires are efl ctively separated from each other and theossibility of a shortcircuit occurring minimized by reason of the closecontact between the engaging surfaces of the insulating blocks, and moreparticllll ularlv by reason of the tongue and groove interlock betweenthe several insulating blocks.v 1

Obviously, if -a cross connection is to be made with four branches, thearmor sections of the coupling will be given the appro riate cross formand two sets of similar L-shaped insulating blocks or members will beprovided to fit the interior of the armor coupling. the insulatingblocks being provided with appropriately formed mati tongues and groovesto efiect the d interlock between these members.

receive and interlock with the convolutions of the cable armor, eachhalf of the coupling armor being adapted to receive an insulating block,one of which may be identical with that shown in Fig. 9, comprising acylindrical body 20 with recesses 21 and 22 in each end connected bylongitudinally spaced grooves 23 and 24 and an intermediate groove 25.The mating insulating section is preferably similar to that shown in.Fig.

9, except that it is provided with a .tongue which meshes with thegroove 25.

In applying this type of coupling to join the ends of two armoredcables, the ends of the respective cables are prepared as illustrated inFig. 10, the bared ends of the wires being twisted together and unitedby solder and the wires laid in the grooves 23 and.

24 of the insulating section .20, with the respective ends I) of theintermediate insulation occupying the inner recesses 22' in theinsulating block and the inner ends of the cable armor occupying thecorresponding recesses 21. The grooves 5 in the respective 1 ends ofthearmor sections of the coupling engage the convolutions on the armorcable, as illustrated, so that, when the tWo sections of the couplingarmor are interlocked by the engagement of the hook flanges thereon, theends of the cables are coupled rigidly together and all strains-on thewires d, d are relieved. It will be noted that the bared portionsofthewire are separated by the entire body of the insulation between thegrooves in'which the Wires rest, and also by the tongue and grooveconnection between the sections of the insulation.

It will be apparent that the same type of coupling may be employed inconnection with multiple wire cables. and Fig. 12 illustrates theadaptation of the coupling to a three-wire cable, in whlch case theinsulating blocks are provided with two sets of interlocking tongues andgrooves running longitudinally, with a conduit for the third wirebetween the tongue and groove connections,

From the foregoing explanation, it will be apparent that a couplingconstructed and applied in accordance with the invention possesses manyadvantages over the types heretofore in use, in that it insures a higherdegree of insulation at the joints between and the wires, completelyeliminates all tension and external stresses on the wires which mighttend to rupture the ioint, and enables the joint to be efi'ected with aminimum loss of the armored cable. By forming the armor sections orhousing members of the coupling of suitable metal and casting theinsulatingvsections of a proper material, it will be apparent that thecoupling may be formed in standard sizes to fit any sizes of cable, andthat the coupling may be effected at a minimum of labor and expense withthe assurance that the joint at the coupling will possess practicallythe same inherent strength as the cable, so that danger of ru ture atthejoint is racticall eliminated.

%V P y hat I claim is: s -1. A coupling 'for armored cablesv comprisinglongitudinally interlocking matingarmor sections having end portionsmeshing .with the cable armor, and complementary insulating blocksfitting within the mating armor sections, said blocks having matinggrooves to form wire-receiving conduits and mating tongue and grooveconnections between said sections.

2. A coupling for-armored cables com prising longitudinally interlockingmating armor sections having internally threaded end portions meshingwith the helical convolutions of the cable armor, and complementaryinsulating blocks fitting within the mating armor sections, said blockshaving mating grooves to form wire-receiving. conduits and mating tongueand groove connections between said sections.

3. A coupling for armored cables com-.

prising half tubular armor sections having interlocking hook flangesalong their meeting edges and internallv threaded end portions meshingwith the helical convolutlons of the cable armor, andcomplementaryinsulating blocksfitting within the mating armor sections,said blocks having matin grooves to form wire-receiving conduits anmating tongue and groove connections between said sections. A

4. A coupling for armored cables comrising half tubular armor sectionshaving 1nterlocking hook flanges along their meeting edges andinternally threaded end por-' tions meshing with the helicalconvolutions of the cable armor, and complementary insulating blocksfitting within the mating armor sections, said blocks having chamberedends to receive the ends of the cable armor and insulation and mating,tongue groove connections between said sections.-

In testimony whereof I aflix my signa- Ill

